mscroggs.co.uk
mscroggs.co.uk

subscribe

Puzzles

Reverse bases

Find two digits \(a\) and \(b\) such that \(ab\) in base 10 is equal to \(ba\) in base 4.
Find two digits \(c\) and \(d\) such that \(cd\) in base 10 is equal to \(dc\) in base 7.
Find two digits \(e\) and \(f\) such that \(ef\) in base 9 is equal to \(fe\) in base 5.

Show answer & extension

Tags: numbers, bases
If you enjoyed this puzzle, check out Sunday Afternoon Maths VII,
puzzles about numbers, or a random puzzle.

Archive

Show me a random puzzle
 Most recent collections 

Advent calendar 2020

Advent calendar 2019

Sunday Afternoon Maths LXVII

Coloured weights
Not Roman numerals

Advent calendar 2018


List of all puzzles

Tags

symmetry people maths range proportion sport regular shapes multiples volume irreducible numbers logic algebra pascal's triangle crosswords addition triangle numbers folding tube maps palindromes polygons averages perfect numbers graphs menace angles star numbers quadrilaterals ellipses rugby parabolas money chocolate probability bases elections means chess median dodecagons chalkdust crossnumber digits rectangles cryptic clues gerrymandering planes coordinates balancing functions ave the only crossnumber spheres number multiplication shapes probabilty books partitions crossnumbers scales factorials perimeter routes colouring christmas floors 3d shapes integers lines numbers dates surds coins square numbers squares triangles mean advent wordplay hexagons games indices quadratics percentages doubling geometry sums factors circles crossnumber products remainders sequences complex numbers tiling area cube numbers unit fractions prime numbers calculus speed odd numbers square roots dice combinatorics fractions shape grids arrows 2d shapes clocks digital clocks trigonometry division time sum to infinity cryptic crossnumbers taxicab geometry integration cards differentiation dominos

Archive

Show me a random puzzle
▼ show ▼
© Matthew Scroggs 2012–2021